Transponder Problem?

[jsstevens]

I was going flying this morning out of Orlando Executive, KORL. I did all the normal things, took off and some 1200 in the air I get a call from the tower: "Recycle your transponder." I did, and they reported no difference. I observed no response light. I checked the circuit breakers (none kicked) and asked if they had it now. Nope. So I aborted. Went back in. Got queried about my altitude a couple of times as I went around the pattern, so they still couldn't see me. After landing, while taxiing back in I saw the response light come on and stay on for an extended time (several seconds). Then nothing more.

Once at the tie down, I asked the club instructor (who was preflighting the plane next door) if there was a trick to this transponder. He said "ATC is probably wrong. The antenna is at [OIA] so you may have to roll enough to expose the antenna on the belly so they can see you." Hmm. Well I certainly rolled plenty going around the pattern and they still couldn't see me.

He flew the plane later in the day and left a voice mail that the transponder worked fine. Remember to roll enough to expose the antenna.

So, I wonder: Is this an intermittent transponder problem? Am I just to careful (ATC didn't tell me to come back, but I'm in a mode C veil)?

Opinions?
John

 

[tonycondon]

how old is it? sometimes these things get flaky with old age.

 

[GCA319]

I was going flying this morning out of Orlando Executive, KORL. I did all the normal things, took off and some 1200 in the air I get a call from the tower: "Recycle your transponder." I did, and they reported no difference. I observed no response light. I checked the circuit breakers (none kicked) and asked if they had it now. Nope. So I aborted. Went back in. Got queried about my altitude a couple of times as I went around the pattern, so they still couldn't see me. After landing, while taxiing back in I saw the response light come on and stay on for an extended time (several seconds). Then nothing more.

Once at the tie down, I asked the club instructor (who was preflighting the plane next door) if there was a trick to this transponder. He said "ATC is probably wrong. The antenna is at [OIA] so you may have to roll enough to expose the antenna on the belly so they can see you." Hmm. Well I certainly rolled plenty going around the pattern and they still couldn't see me.

He flew the plane later in the day and left a voice mail that the transponder worked fine. Remember to roll enough to expose the antenna.

So, I wonder: Is this an intermittent transponder problem? Am I just to careful (ATC didn't tell me to come back, but I'm in a mode C veil)?

Opinions?
John

You shouldn't have to roll your airplane into a steep bank in order to get the transponder working...

 

[jsstevens]

how old is it? sometimes these things get flaky with old age.

I don't know exactly. The plane is a 1973 C-172. The transponder has little levers that you move up and down to set the code. I've never seen one like it before. It looks like it could be original equipment.

John

 

[jsstevens]

You shouldn't have to roll your airplane into a steep bank in order to get the transponder working...

To be fair, he didn't say a steep bank-just enough to expose the antenna. But I'm with you, I've never had to do that before.

 

[tonycondon]

yea its an antique

 

[Jeff Oslick]

First item is to clean off the antenna and see if that helps (seriously, a film of grime on the transponder antenna really messes up it's performance), next I'd check the contacts where it plugs into the rack, since it worked after landing, there may be a loose connection there.

Jeff

 

[Velocity173]

First item is to clean off the antenna and see if that helps (seriously, a film of grime on the transponder antenna really messes up it's performance), next I'd check the contacts where it plugs into the rack, since it worked after landing, there may be a loose connection there.

Jeff

Yeah I have that problem with mine. Never had any bad reports after I cleaned all the oil/grime build up.

 

[wby0nder]

Sweet! I've been having poor reports on mine too and my I.A. told me to clean the antenna and I thought, "yeah right, like that's gonna help!". Will be cleaning it before next flight!

 

[Tom-D]

I don't know exactly. The plane is a 1973 C-172. The transponder has little levers that you move up and down to set the code. I've never seen one like it before. It looks like it could be original equipment.

John

That's an old Cessna ARC, flip switch transponder, one of the best ever built, they are probably the only good product they built. but they are getting old.

club aircraft, probably won't get replaced until it smokes.